Abstract: The Chuan No.05 well, located in the Sichuan-Yunnan region, is a seismic observation well located at the west end of the Xigeda-Yuanmou fault. The statistical data of the coseismic response of the well show that the response time of the well dynamic ground water level is 1~85 min and the response amplitude is 1~29 mm. The response modes include oscillation type, pulse type, step-change type and step-change-oscillation type. By calculating the seismic distribution range and the seismic energy density of the well, the seismic reflection ability of the well is analyzed. The results show that when the epicentral distance (r) and magnitude (M) meet the relation logr≤0.95M-3.35, the dynamic ground water level of the Chuan No.05 wells more likely to have a coseismic response. For earthquakes above M_S8.0, the well has a significant ability to reflect earthquakes, and the variation range of water level is greatly constrained by the magnitude and epicenter distance. It is found that the energy density e(r) of the dynamic ground water level for the response of the Chuan No.05 is in the range of 10^-6~10^-2 J/m³, and when the energy density e(r)≥10^-3 J/m³, the water temperature can produce post-seismic step change.

Key words: Chuan No.05 well, Dynamic ground water level, Seismic energy density, Response characteristic, Earthquake reflecting